A CSMA/CA based TDMA Protocol for MAC Layer in Wireless Sensor Networks

Abstract

This paper is presented as hybrid protocol for MAC layer in Wireless Sensor Networks (WSNs). It combines contention and schedule-based methods. Time slots are assigned at deployment and reassigned when significant changes in topology. Time slot assignment is designed by semidistributed manner. A base station is considered as a master only for its one-hop children because nodes are also memory (buffer)-constrained ones in real world. When a base station sends token to its neighboring nodes all the way through the largest-hop nodes and token is sent back to the base station causing the overflow of buffer or the time slot assignment table may be damaged during token is passing through all the nodes. To avoid this problem, time slot assignment is only considered as the two-hop neighbors from each parent.